This question already has an answer here:
I am getting the error
PHP Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 33292313 bytes)
when i am running my pagination function and i don't know what is happening and/or why i'm getting the error.
From what i've seen on the other questions here, most people recommend that i change the memory limit in the php.ini file.However, i would like to know why this error is happening and what i can do to prevent it form happening in the future.
From this question Meaning of "Fatal error: Allowed memory size of x bytes exhausted (tried to allocate y bytes)"? i can see that the php script has exceeded the allocated memory limit (duh!) but it isn't really helpful.
Question:
My Pagination function:
function Pagination( $connection, $num, $page, $view ) {
$view=$view;
//Results per page
$pagerows=10;
//Tells us the last page number
$last=ceil( $num/$pagerows );
// Establish the $PaginationNav variable(used to navigate the paginated results)
$PaginationNav = '';
//Check how many pages of results there are
//If there is more than 1 page
if( $last != 1 ) {
//Check if we are on page 1, if so we don't need the 'previous' link
//We are on page one
if( $page == 1 ) {
//Adds the current page
$PaginationNav .= $page;
//Adds the next 3 pages to the pagination
for( $i=$page+1;$i<$last;$i++ ) {
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$i\">$i</a>";
if( $i > $page+4 ) {
break;
}
}
$PaginationNav .= "...";
//Adds the last page to the pagination
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$last\">$last</a>";
//Adds the next page button
$next=$page + 1;
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$next\">Next </a> ";
} else {
//we are not on page 1
//Adds the previous button to pagination
$previous=$page - 1;
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$previous\">Previous</a>";
//Adds the current page
$PaginationNav .=$page;
//Adds the left navigations
for( $i = $page-4;$i=$page;$i++ ) {
if( $i>0 ) {
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$i\">$i</a>";
}
}
//Adds the right navigations
for( $i=$page;$i<$last;$i++ ) {
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$i\">$i</a>";
if( $i > $page+4 ) {
break;
}
}
//Adds the last page to the pagination
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$last\">... $last</a>";
//Adds the next page button
$next=$page + 1;
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$next\">Next </a> ";
}
}
//There is only one page
if( $last == 1 ) {
$PaginationNav .= $page;
}
return $PaginationNav;
}
There was a comment on one of the question i've seen that states that simply increasing the memory limit isn't a good substitute for good coding. I agree, and i would like to change that code to be better instead of simply mindlessly increasing memory.
P.S I've no formal training in programming, and am learning simply by throwing myself into coding, so i apologise if the answer is pretty obvious.
</div>
you have:
for($i = $page-4;$i=$page;$i++) // change to ==
{
if($i>0)
{
$PaginationNav .= "<a class='Pagination' href=\"$_SERVER[PHP_SELF]?view=$view&page=$i\">$i</a>";
}
}
you are assigning $page to $i in $i=$page and it will return $page (probably a positive number) every time, which will result in true condition. Change it to ==
As galchen caught, you had an incorrect for loop terminator, causing an infinite loop that was finally broken by running out of memory. Increasing the memory limit would not have fixed this problem.
I'd like to offer my rewrite of your Pagination function. I haven't tested it, but I believe it will produce more consistent results overall.
function Pagination($connection,$num,$page,$view,$pagerows=10) {
//Tells us the last page number
$last = ceil($num/$pagerows);
if( $last == 1) return $page;
// Establish the $PaginationNav variable(used to navigate the paginated results)
$PaginationNav = '';
// Helper function to reduce repeated code - great if you want to change the link!
$addpage = function($p,$custom="") use (&$PaginationNav) {
$PaginationNav .= "<a class='Pagination' href='".$_SERVER['PHP_SELF']."?view=".$view."&page=".$i.">".($custom ? $custom : $i)."</a>";
};
//Check if we are on page 1, if so we don't need the 'previous' link
if( $page != 1) {
//Adds the previous button to pagination
$addpage($page-1,"Previous");
}
if( $page > 4) {
//Adds the first page to the pagination
$addpage(1);
$PaginationNav .= "...";
}
//Adds the left navigations
for($i = max(1,$page-4); $i < $page; $i++) {
$addpage($i);
}
//Adds the current page
$PaginationNav .= $page;
//Adds the right navigations
for($i=$page; $i<$last && $i < $page+4; $i++) {
$addpage($i);
}
if( $page < $last-4) {
$PaginationNav .= "...";
//Adds the last page to the pagination
$addpage($last);
}
if( $page != $last) {
//Adds the next page button
$addpage($page+1,"Next");
}
return $PaginationNav;
}